1. Field of the Invention
The present invention relates to improvement of a method of and apparatus for transporting a strip of photographic printing paper (herein-after referred to as a printing paper) in a printer wherein the method and apparatus are practiced by way of the steps of loading printing paper, allowing it to be subjected to exposure, forming a loop of the printing paper and thereafter delivering it to the next process. More particularly, it relates to a method of and an apparatus for transporting printing paper in a printer in the case where an automatic developing machine is installed behind the printer wherein improvement is made so as to exhibit remarkable advantageous effects when a photographic treating machine is so constructed that a series of treating operations ranging from exposing to developing of printing paper are carried out automatically.
2. Description of the Prior Art
As disclosed in the specifications of U.S. Pat. No. 4,136,946 (corresponding to British Patent No. 1,550,048) and German Laid-Open Patent No. 2,244,960, a conventional photographic treating machine is so constructed that an automatic developing machine is installed behind a printer in alignment with the latter and a series of treating operations ranging from exposure on printing paper to developing are carried out automatically. Specifically, in the conventional photographic treating machine printing paper in the form of a roll is supported in a printing paper feeding section in such a manner that it can be fed therefrom, it is intermittently fed by a predetermined length and it is subjected to exposure at a time of intermittent stoppage. To compensate for the difference between the short time required for the printing operation and the long time required for the developing operation in an automatic developing machine as the well as difference between the manner of intermittent transportation of printing paper after the intermittent feeding operation on the printer side and the manner of the developing operation on the developing machine side accompanied by the transportation of printing paper at a predetermined transporting speed, there is proposed the formation of a loop between an exposure section where exposing is effected for the printing paper in a printer and a feeding section where printing paper is delivered to an automatic developing machine.
As described in the specification of U.S. Pat. No. 4,136,946 (corresponding to British Patent No. 1,550,048), formation of a loop is achieved by way of the steps of opening a light shielded lid disposed at a loop formation place, bringing the foremost end part of printing paper to a delivery port by manual operation and then closing the light shielded lid. However, due to arrangement made for the photographic treating machine in that way there is caused some loss of the end part of printing paper exposed in vain and this loss can not be neglected from the viewpoint of economics or waste. To obviate the above problem there is proposed a transporting means for printing paper as disclosed in the specification of the abovenoted patent but the thus proposed transportation means requires many parts and components such as guide, roller or the like, resulting in the structure of the photographic treating machine becoming complicated. Thus, trouble or failure tends to take place during transportation of printing paper.